1. Field of the Invention
The present invention relates generally to the preparation and use of biological tissue adhesives which rely on combining fibrinogen and thrombin. More particularly, the present invention relates to an improved fibrin sealant (FS) which incorporates various biological and/or non-biological agents into its composition. The invention further relates to a novel method of application for such a sealant whereby the sealant and accompanying agent(s) are delivered to discrete sites within the body and held in place due to the bio-static characteristics of the improved sealant.
2. Related Art
Fibrin sealants, and glues, are well known and are used extensively in various clinical settings. Such sealants are indicated as adjuncts to hemostasis in surgeries when control of bleeding by conventional surgical techniques, including suture, ligature, and cautery is ineffective or impractical. For instance, fibrin sealants have been shown to be effective in patients undergoing reoperative cardiac surgery (J. Rousou, et al., Journal of Thoracic and Cardiovascular Surgery, vol. 97, no. 2, pp 194–203, February 1989), spinal neurosurgery (P. Knoringer, Fibrin Sealing in Spinal Neurosurgery, 1986), general cardiac surgery (P. M. McCarthy, et al., Fibrin Sealant: The Cleveland Clinic Experience, 1991), pulmonary surgery, (M. Dahan et al., The Importance of Biological Glue for the Prevention of Air Leakage in Pulmonary Surgery, Materials and Methods, pp 113–116, 1991), liver and spleen surgery (H. W. Waclawiczek, Fibrin Sealing in Liver and Spleen Surgery, 1994), and neurosurgical procedures ©. Shaffrey, et al., Neurosurgery, vol. 26, No. 2, pp 207–210, 1990).
Use of fibrin glue and methods for its preparation and use are described by Hirsh et al. in U.S. Pat. No. 5,643,192. Hirsh discloses the extraction of fibrinogen and thrombin components from a single donor, and the combination of only these components for use as a fibrin glue. Marx, U.S. Pat. No. 5,651,982, describes another preparation and method of use for fibrin glue. Marx provides a fibrin glue with liposomes for use as a topical sealant in mammals. The preparation and use of a topical fibrinogen complex (TFC) for wound healing is known in the field. PCT Application No. PCT/US95/15876, PCT Publication No. WO96/17633, of The American Red Cross discusses TFC preparations containing fibrinogen, thrombin, and calcium chloride, for example, at pages 16–18 of PCT Publication No. WO96/17633.
Still, there remains a need for a tissue sealant that may be delivered to discrete sites within the body and that has the capacity to localize and mediate the release of drugs and/or other biological and non-biological agents, which may be embedded in the sealant composition.